JP2000315477A - Fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life fluorescent lamp having excellent workability and improved luminous flux maintaining factors and preventing blackening spots, etc., from being generated in the fluorescent lamp of high bulb wall load. SOLUTION: In this fluorescent lamp, the bulb wall load is 0.13 W/cm2 or more, and a glass tube contains in a weight ratio 57%-78% of SiO2, over 0% to 6% of BaO, 2%-10% of SrO, 6% or under of CaO, 6% or under of MgO, 4%-11% of Na2O, 2%-11% of K2O, 4% or under of Li2O, 0.5%-35 of B2O3, below 3% of P2O5, 1%-6% of Al2O3, over 0% to 1.5% of Sb2O3, 0.5% or under of Fe2O3, and 0.5% or under of SO3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp which is operated under a high load.

[0002]

2. Description of the Related Art In recent years, in addition to conventional straight tube fluorescent lamps and round fluorescent lamps, various types of fluorescent lamps such as compact fluorescent lamps and light bulb fluorescent lamps have been put on the market. The compact design of the fluorescent lamps contributes to the creation of various lighting spaces by saving space, increasing brightness, and increasing output.

[0003] Conventional fluorescent lamps use a technique for reducing the diameter of an arc tube, heating and bending a straight glass tube (bending), and bridging two glass tubes for compactness. . In particular, a technique for obtaining a double emission area by connecting two glass tubes in a bridge is used.
A compact fluorescent lamp having a long discharge path and a compact fluorescent lamp has been developed by performing a bonding of six, a bonding of six, and a bonding of eight.

In recent years, the space saving of a fluorescent lamp using a straight arc tube has been advanced, and an arc tube using a straight glass tube having an outer diameter of 16 mm or less has been developed.

Various types of glass are used in the arc tube of a fluorescent lamp, and the expansion coefficient, softening temperature,
It is necessary to consider that the physical properties such as the working temperature are different, and that the glass workability is also considered. It is also necessary to consider inexpensiveness, strength and durability. In general, soda-lime glass, which is inexpensive and has appropriate strength, and lead glass, which has better workability, are mainly used as arc tube materials. Since such a glass has a low processing temperature, a bent arc tube can be easily formed.

[0006]

The conventional fluorescent lamp is
Along with the downsizing, there is a problem that the luminous flux maintenance rate decreases, and black spots or dark spots occur with the elapse of the lighting time, and the lamp performance is significantly reduced. In addition, there is a problem that the luminous flux maintenance factor is significantly reduced due to high-output lighting by high frequency, lighting in an enclosure formed of a glove and a case, or a sealing device such as a ceiling. This decrease in the luminous flux maintenance factor is considered to be caused by adsorption of mercury existing in the discharge space to the inner wall of the arc tube, coloring of glass by ultraviolet rays, reduction in luminance of the phosphor, and the like. Above all, fluorescent lamps with a high tube wall load, which is expressed by the lamp power consumption per area inside the arc tube, are particularly prone to darkening and black spots of the arc tube due to mercury compounds during operation, and therefore, maintaining the luminous flux. The rate has also declined significantly.

[0007] In particular, in a bulb-type fluorescent lamp in which an arc tube is provided in an envelope composed of a glove and a case,
During lighting, the temperature of at least part of the arc tube is 100 ° C.
Because of the above, the luminous flux maintenance rate is significantly reduced. Also,
A compact fluorescent lamp in which a glass tube is bent or joined by a bridge has a problem in that the glass-processed portion is significantly colored during lighting and impairs the appearance.

As described above, the electric and the electric power applied to the arc tube are
Thermal load is increasing with the increase in the output of fluorescent lamps.
In recent years, there has been a tendency to increase, and it is desired to improve the luminous flux maintenance rate of a fluorescent lamp having a high load and prolong its life.

On the other hand, soda lime glass, which is inexpensive and has good workability, has conventionally been used as a material for the arc tube of a fluorescent lamp as a glass composition for a glass tube used for the arc tube of such a fluorescent lamp. However, this soda-lime glass
Very high sodium content. Sodium is indispensable for improving the glass processability, but when the content is large, the glass processability is improved, but sodium is easily precipitated on the glass surface. Therefore, when a large amount of sodium is contained, mercury easily adheres to the inner surface of the arc tube, which causes coloring inside the arc tube.

For example, in a thin tube fluorescent lamp having an inner diameter of an arc tube of 15 mm or less or a compact fluorescent lamp having a high tube wall load, the luminous flux maintenance factor is significantly reduced.

This is due to the fact that the area inside the arc tube with respect to the power consumption is extremely small, so that the intensity of ultraviolet rays, ion bombardment and temperature load per unit area are so large as compared with those of conventional fluorescent lamps.

FIG. 1 shows the load on the tube wall of various fluorescent lamps and the luminous flux maintenance rates of the lamps. As is clear from FIG. 1, in the conventional fluorescent lamp indicated by the symbol x,
It can be seen that when the tube wall load is 0.13 W / cm ² or more, the luminous flux maintenance factor is extremely reduced. Tube wall load is 0.13W /
Those having cm ² or more correspond to so-called compact fluorescent lamps having ^two or more bridge joints or ^two or more bent portions having an arc tube inner diameter of 15 mm or less.

In general, lead glass as a conventional arc tube material has a composition of 20% or more of PbO and Na ₂
O is contained in about 6 to 10%, and has good workability and durability.
Since it is relatively inexpensive, it is used for various fluorescent lamps. However, since it contains lead, it is necessary to suppress the use of lead in consideration of the global environment. JP-A-6-20
As disclosed in Japanese Patent No. 6737, a composition of an electric lamp glass as a substitute for the lead glass is reported. However, such a tube wall load was insufficient to improve various disadvantages when applied to a fluorescent lamp as high as 0.13 W / cm ² .

Further, in order to improve the drawbacks of fluorescent lamps using glass containing a large amount of sodium, a protective film is provided on the inner surface of the glass tube to prevent adhesion of mercury and to improve lamp characteristics such as a luminous flux maintenance factor. It is known. A commonly used material is coated with a metal oxide layer such as alumina or silica. However, in a fluorescent lamp with a high tube wall load, the bulb must be coated with a thickness of 1 μm or more in order to maintain the performance, but there is a problem that the fluorescent film is easily peeled off in the bulb processing step.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and improves the luminous flux maintenance rate by preventing darkening and black spots of a fluorescent lamp having good workability and a high tube wall load. It is an object of the present invention to provide a compact fluorescent lamp with a long life that can be used.

[0016]

According to the first aspect of the present invention, there is provided:
Fluorescent lamps are placed inside a glass tube with a phosphor layer applied to the inner surface.
Mercury and noble gas are sealed, and tube wall load
But 0.13W / cm ^TwoAnd the glass tube
However, the weight ratio of SiO_TwoFrom 57% to 78%, BaO
More than 0% and 6% or less, SrO 2% or more and 10% or less,
CaO 6% or less, MgO 6% or less, Na_TwoO 4%
Not less than 11%, K_TwoO 2% or more and 11% or less, Li_TwoO
Less than 4%, B_TwoO_Three0.5% or more and 3% or less, P_TwoO_FiveTo
Less than 3%, Al_TwoO_ThreeFrom 1% to 6%, Sb_TwoO_ThreeTo 0
% And 1.5% or less, Fe_TwoO_Three0.5% or less, SO
_ThreeOf 0.5% or less.

[0017] Thus, by having the same degree of workability, strength and durability as the conventional soda glass, and reducing the diffusion of sodium in the glass to the inner wall of the arc tube,
The luminous flux and the luminous flux maintenance rate, which are characteristics of the fluorescent lamp, can be remarkably improved.

According to a second aspect of the present invention, in the fluorescent lamp according to the first aspect, the arc tube is housed in a glove made of glass or resin.

Thus, in the fluorescent lamp having the bent arc tube at the time of high temperature lighting in which the envelope of the arc tube is sealed, it is possible to prevent the occurrence of dark spots and black spots and to improve the luminous flux maintenance rate. .

According to a third aspect of the present invention, in the fluorescent lamp according to the first or second aspect, a protective film is formed between an inner surface of the glass tube and the phosphor layer. I have.

As a result, the processing characteristics can be maintained and the coloring of the glass, the adsorption of mercury, and the movement of sodium can be prevented, so that the luminous flux maintenance factor of the fluorescent lamp can be greatly improved.

According to a fourth aspect of the present invention, in the fluorescent lamp according to the third aspect, the protective film is a metal oxide, and at least one of aluminum, silicon, yttrium, cerium, and titanium is used as an element. It has a configuration including:

By using a small amount of inexpensive and easily available metal oxide, the effect of preventing adsorption of mercury, suppressing diffusion of sodium, and preventing deterioration of glass from ultraviolet rays can more effectively increase the luminous flux maintenance factor of the fluorescent lamp. It can be improved.

According to a fifth aspect of the present invention, in the fluorescent lamp according to any one of the first to fourth aspects, an inner diameter of the glass tube is 15.0 mm or less.

As a result, the luminous flux maintenance factor of a fluorescent lamp using a thin tube, which has been impossible to improve the luminous flux maintenance factor, can be remarkably improved.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION In a fluorescent lamp according to the present invention, the glass composition has a Na ₂ O content of 4% or more and 11% by weight.
It is as follows. When the amount of Na ₂ O added exceeds 11% by weight, the workability is good, but the luminous flux maintenance factor of the arc tube decreases markedly. If the weight ratio is less than 4%, the processing temperature of the glass becomes high, and the viscosity becomes higher than that of the soda-lime glass conventionally used, so that the glass is unsuitable as a tube glass.

K ₂ O and Li ₂ O, together with Na ₂ O, have the effect of lowering the processing temperature by lowering the viscosity of the glass. In addition, since the alkali mixing effect has an effect of preventing sodium ions from eluting to the surface, K ₂ O, L
It is possible to mix i ₂ O with Na ₂ O to make the glass workability equal to that of conventional soda-lime glass. But,
It is not preferable to increase the content of K ₂ O and Li ₂ O, since the water resistance and strength of the glass decrease.

K ₂ O is preferably added in a weight ratio of 2% or more and 11% or less, and if it is less than 2%, no alkali mixing effect can be obtained, and if it exceeds 11%, devitrification is caused.

In the present invention, the linear expansion coefficient of glass can be adjusted by adding Li ₂ O at a weight ratio of 4% or less. However, if it exceeds 4%, the expansion coefficient becomes too high, and it becomes unsuitable as glass for a tube.

Further, BaO and SrO are added in order to maintain physical properties comparable to those of soda-lime glass. BaO and SrO become relatively large divalent ions in glass and have an effect of preventing diffusion of sodium ions. However, when added in large amounts, both cause crystallization and are prone to devitrification. Suitable addition amounts are up to about 10% by weight each.

In addition, the addition of B ₂ O ₃ and P ₂ O ₅
It can prevent the devitrification of glass due to the presence of O and SrO. B ₂ O ₃ and P ₂ O ₅ are materials constituting the glass network structure. By adding a small amount, it is possible to increase the glass strength and reduce the processing temperature. In addition, since the water resistance can be improved, there is an effect that the durability to the use of the fluorescent lamp using the glass tube is improved.
Accordingly, the movement of sodium ions is prevented by the effect of strengthening the structure of the glass.

As mentioned above, BaO and SrO are
It is effective to add to the glass composition together with ₂ O ₃ and P ₂ O ₅ . However, since B ₂ O ₃ and P ₂ O ₅ have the property of phase separation when the added amount is increased, it is necessary to avoid using them in large amounts. BaO has a weight ratio of more than 0% to 6% or less. Sr
O is 2% to 10% by weight, and B ₂ O
_3, more than 3% by weight ratio of 0.5% or more, P ₂ O ₅ is preferably added in a range of weight ratio of 3%. In particular, Ba
The combined weight ratio of O and SrO is preferably 11% or less, and the weight ratio of BaO to SrO is
It is preferable to add ₂ O ₃ and P ₂ O ₅ so as to be １ ／ or less.

The addition of CaO and MgO imparts workability as a tube glass and an appropriate strength. Also,
In order to prevent the devitrification of the glass and because it is inexpensive, it is preferable to add it instead of other metals. CaO is 6 by weight
% Or less, and MgO in a weight ratio of 6% or less is suitable. CaO
When MgO and MgO are added in excess of 6% by weight, the effect of suppressing devitrification is lost.

When a small amount of Sb ₂ O ₃ or Fe ₂ O ₃ is added, the transmittance of glass is increased by the defoaming action, so that the luminous flux of the fluorescent lamp can be improved. It should be noted that it also contributes to the improvement of the luminous flux maintenance factor. In particular, it has been found that a fluorescent lamp having a bent arc tube, such as a bulb-type fluorescent lamp, has a high effect. These materials improve the luminous flux maintenance rate depending on the added amount, but are preferably of such an extent that the glass is not colored. Therefore, Sb ₂ O ₃ 1.5% exceeds the weight ratio of 0 the following, Fe ₂ O ₃
Is preferably added in a weight ratio of 0.5% or less. If the weight ratio of Sb ₂ O ₃ exceeds 1.5% and the weight ratio of Fe ₂ O ₃ exceeds 0.5%, the luminous flux of the lamp may be reduced.

It is preferable to add SO ₃ as a fining agent to prevent coloring by Sb ₂ O ₃ and Fe ₂ O ₃ . Preferably, SO ₃ is added at a weight ratio of 0.5% or less.

It is preferable to add ZnO, TiO ₂ , CeO _2, etc. in order to increase the visible light transmittance of the glass and prevent the deterioration of ultraviolet rays.

[0037] SiO ₂ is an important substance as a glass constituting material. However, if the weight ratio is 50% or less, devitrification due to recrystallization of each additive metal and extremely lowering of glass strength are caused. Therefore, it is necessary to add more than 50% by weight, and in the present invention, the range of 57% to 78% by weight is most suitable.

Al ₂ O ₃ has an effect of preventing devitrification of glass and increasing water resistance. Therefore, it is preferable to add a weight ratio of 1% or more and 6% or less, and if it is less than 1%, devitrification prevention and water resistance cannot be added, and if it exceeds 6%, the glass forming temperature and the glass processing temperature increase. Therefore, it is not preferable.

As described above, by using the above glass composition, the binding between mercury and sodium ions in the arc tube can be reduced, and the luminous flux maintenance factor of a compact fluorescent lamp or a bulb-type fluorescent lamp can be particularly reduced. Can be greatly improved.

Further, between the inner surface of the glass tube and the phosphor layer,
It is preferable to provide a protective film and use it in combination with a glass tube having the composition of the present invention. The effect of the protective film is to improve the luminous flux maintenance rate by reducing the adhesion of mercury to the glass surface on the inner wall of the arc tube. As a specific material, a metal oxide layer containing at least one element of aluminum, silicon, yttrium, cerium, and titanium is preferable.

In order to prevent the movement of sodium ions into the arc tube, it is important to block the movement path of sodium. The primary particle diameter of the protective film material is 0.01 to 0.1 μm
A sufficient effect was confirmed by using m. If such a protective film material is used, even a thin film having a thickness of 1 μm or less has an effect of improving the luminous flux maintenance rate of a compact fluorescent lamp, a bulb-type fluorescent lamp, and the like. And unlike before,
By forming the film as a thin film, the glass workability during lamp production is not significantly changed, and the appearance problem due to film peeling is less likely to occur.

As a material for the protective film, the most common method is to apply an organic metal solution, a sol solution, or a fine powder dispersion containing the above-mentioned elements by dipping. Since the protective film is formed through baking, the starting material may not be an oxide, and a more uniform protective film can be formed by combining various organic material dispersants and binders.

FIG. 1 compares the tube wall load of the fluorescent lamp and compares the luminous flux maintenance ratio after the lighting life test for 2500 hours. Luminous flux maintenance rate is 100% for 100 hours
Is the luminous flux maintenance rate after lighting for 2500 hours. In the figure,
The symbol ○ indicates the result of the fluorescent lamp according to the present invention, and the symbol × indicates the result of the conventional fluorescent lamp.

As is clear from the measurement results shown in FIG.
A conventional fluorescent lamp having a tube wall load of 0.13 W / cm ² or more has a luminous flux maintenance factor of 80% or less, whereas the fluorescent lamp according to the present invention has a tube wall load of 0.13 W / cm ² or more. Therefore, the luminous flux maintenance factor can be maintained at 80% or more, and the fluorescent lamp of the present invention can improve the luminous flux maintenance factor of about 10% or more after 2500 hours of operation as compared with the conventional fluorescent lamp. did it.

As a fluorescent lamp having a high tube wall load,
For example, as shown in FIG. 2, one end portions of two straight tubular glass tubes are connected to each other by bridge joining and integrated, electrodes are provided at both ends of the integrated glass tube, and the integrated glass tubes are integrated. A structure in which a phosphor layer is formed on the inner surface of a glass tube, a mercury and a rare gas are sealed therein to form a light emitting tube, and a base is fixed to an electrode side end of the light emitting tube ( FPL).

In addition, compact fluorescent lamps such as FDL and FHT, bulb-type fluorescent lamps in which arc tubes such as EFT and EFG are housed in glass or resin gloves, and fluorescent lamps such as FHF The same effect can be obtained by using the glass tube of a fluorescent lamp having a high tube wall load. Examples of the lighting device include a ceiling light, a downlight, a high-frequency lighting method using an inverter, and a lighting device using a combination thereof. The present invention is effective for such fluorescent lamps and lighting devices.

Hereinafter, embodiments of the present invention will be described.

(Example 1) Various glass compositions were examined, and glass composed of various glass compositions was prepared and evaluated. FIG. 3 shows the composition and characteristics of the various glass composition glass tubes evaluated. Further, all the compositions in the figures are described in weight percentage. The coefficient of linear expansion of each glass composition is the coefficient of linear expansion at a temperature of about 25 to 300 ° C. The softening temperature of each glass is such that the viscosity of the glass itself is 107.6 dPa. This is the temperature when the temperature reaches s. The working temperature is set such that the viscosity of the glass itself becomes 104 dPa. s
Is the temperature at which The transmittance of each glass was determined by measuring the transmittance of a glass tube with a transmittance spectrometer and calculating the transmittance per 1 mm thickness. The measurement of the alkali elution amount of each glass was based on JIS R3502.

The glass composition according to the fluorescent lamp of the present invention (the composition indicated by the present invention 1 in the table (hereinafter referred to as the present invention 1)), and the glass composition according to the fluorescent lamp of the present invention (the present invention in the table) A glass tube having the composition of product 2 (hereinafter referred to as product 2 of the present invention) and the compositions of comparative product 1 and comparative product 2 shown as comparative examples was prepared. That is, various raw material ratios were added as shown in the table, and after melting, a glass tube was produced through a sleeve.

These compositions were easy to mold as glass tubes, and could be easily processed into fluorescent lamp arc tubes. It is considered that the effect of lowering the glass melting temperature was obtained by adding strontium, barium, and boron for the small amount of sodium. In addition, the composition which did not become glass or did not obtain the desired properties was compared with Comparative Product 3 in FIG.
This is shown in Comparative Product 4.

With respect to examples of conventional glass compositions such as soda-lime glass and lead glass, the glass composition and physical characteristics are described in Conventional Products 1 and 2 shown in FIG.

These glass compositions exhibit almost satisfactory physical properties. However, in the present invention, it is necessary to satisfy the luminous flux maintenance factor as the performance of the fluorescent lamp. Actually, the product of the present invention 1, the product of the present invention 2, the comparative product 1, the comparative product 2, the conventional product 1,
The following examples show the results of evaluating how the characteristics change when a lamp is formed using the glass of the conventional product 2.

(Example 2) As a high-load fluorescent lamp, F
HT32W type arc tubes were made of glass having the composition of the present invention product 1, comparative product 1, comparative product 2, conventional product 1, and conventional product 2 shown in FIG. 3, and the lamp characteristics were compared.

First, a glass of various compositions was weighed to an outer diameter of 12.5 m.
m, and processed into a valve having a wall thickness of 1.0 mm, and cut into a total length of 230 mm as a straight glass tube. This glass tube,
After washing with water, a protective film was applied on the inner surface of the glass tube as needed, and a phosphor suspension was applied on the protective film and dried. This valve is burned by a sinter, and one valve is burned off at about the center in two parts. One side burned off by a burner is closed at the same time as the burned out side, and the other is an exhaust pipe. Alternatively, a mount having electrodes was sealed.

The three bulbs were processed in this way into four exhaust thin tubes and two mounted seals, and one arc tube was formed by bridging each other. There are five bridges in total. Finally, only one exhaust thin tube was used, and after heating and evacuation, mercury and a small amount of a rare gas were sealed in the exhaust device, and the exhaust thin tube was closed to produce an arc tube. The base was attached so that it could be mounted on the lighting device.

In this arc tube processing, no particular problem was observed in the product of the present invention 1, the comparative product 1 and the conventional product 1. However, when glass having the composition of the comparative product 2 was used, leakage of the arc tube occurred. About 70% became unlit lamps in a few days.

As a result of the analysis, a mechanical shock was applied during transfer after one valve was burned out to two valves, and a crack at the tip part grew in the final stage, and appeared as a slow leak after evacuation. In particular, when the strength of the arc tube end is compared by performing an iron ball drop test, the comparative product 2 is extremely lower than the glass of the other composition, and has a strength 1/2 that of the product 1 of the present invention. there were. From this, it is considered that the comparative product 2 has low glass strength.

Next, the fluorescent lamps produced using the product 1, the comparative product 1 and the conventional product 1 were turned on at 32 W. The tube wall load is the same, 0.17 W / cm ² . During lighting, the tube wall temperature of the fluorescent lamp was high and exceeded 130 ° C. at the bridge portion.

When the characteristics of the lamps were measured, the initial luminous flux value of the comparative product 1 was reduced by about 5% as compared with the product of the present invention 1 and the conventional product 1 even with the same power consumption. This is considered to be due to the effect of the added amount of barium, and there is a possibility that the excess barium has reduced the initial characteristics of the lamp.

In the life test, lighting is performed for 2.5 hours a day 0.5
The life and the luminous flux were measured in a time-out cycle, and the change with time was investigated.

FIG. 4 shows the luminous flux maintenance ratio of the product 1 of the present invention and the conventional product 1. In comparison, the product 1 of the present invention has an improved luminous flux maintenance rate of about 10% compared to the conventional product 1. In addition, the product 1 of the present invention (shown by a symbol B in FIG. 4) having a configuration in which a protective film was applied was approximately equivalent to the product 1 of the present invention without a protective film (shown by a symbol A in FIG. 4). The luminous flux maintenance rate is improved by 7%. The protective film was made of alumina having an average particle diameter of 0.1 μm as an alumina powder dispersion. The thickness of the protective film was 0.7 μm on average. In the case of the conventional product 1 (indicated by the symbol D in FIG. 4), the degree of improvement of the luminous flux maintenance factor is low, only about several percent, even though the same protective film is applied.

In the conventional product 1 (indicated by symbol C in FIG. 4), a black spot appeared when the lamp was turned on for more than 1000 hours, and gradually spread with the lighting time. Even if a protective film is provided, 20
Since black spots appear after about 00 hours of lighting, it is considered impossible to eliminate the black spots in this glass because the amount of precipitated sodium is fundamentally large. In the glass of the product 1 of the present invention, black spots did not occur at all for 7000 hours of lighting regardless of the presence or absence of the protective film.

As described above, the use of the glass material of the present invention has shown a remarkable improvement in the luminous flux maintenance factor.
It has been found that an effective improvement is possible.

Example 3 The glass of the product 2 of the present invention shown in FIG. 3 is a composition obtained by adding 0.5% of P ₂ O ₃ to the product 1 of the present invention, and the softening point is increased by about 10 ° C. However, the product of the present invention 1
Glass processing was possible without changing the glass processing conditions at all. Using this glass tube, a fluorescent lamp of the FHT type is manufactured and a lighting test is performed at 32 W with a dedicated inverter. After lighting for 2500 hours, a comparison of the luminous flux maintenance rate shows that the conventional product 1 is improved by about 12%. The effect was recognized.
Further, this glass was effective in increasing the intensity of the fluorescent lamp, and the compressive strength of the bridge junction reached 1.3 times the normal strength.

Example 4 A glass tube having an outer diameter of 12.0 mm, a thickness of 1.0 mm, and a thickness of 256 mm was manufactured using the product 1 of the present invention, the conventional product 1 and the conventional product 2 shown in FIG. This glass tube was coated with a protective film and a phosphor and sinter-baked according to Example 1, and then heated twice with a burner to bend twice to produce an arc tube having three bent portions. This arc tube was assembled as a bulb-shaped fluorescent lamp incorporating a transparent glass glove and an electronic circuit. Power consumption is about 14W
And the tube wall load is about 0.14 W / cm ² . Example 1
Similarly, the luminous flux maintenance ratio after lighting for 2500 hours was compared.

As a result, it was confirmed that the glass fluorescent lamp of the product 1 of the present invention was improved by about 12% in luminous flux maintenance rate after lighting for 2500 hours as compared with the conventional product 1. Further, as compared with the conventional product 2, a difference in the luminous flux maintenance ratio of about 5% appeared, and the effect became more prominent in the long term. This is the product of the present invention 1 and the conventional product 2
It is presumed that sodium ion transfer was lower than that of the conventional product 2 in spite of the fact that the amount of sodium was approximately equal to about 7% in the glass composition of No. 2. Therefore, even in a bulb-type fluorescent lamp in which a fluorescent tube is covered with a globe, the glass composition of the present invention can effectively improve the luminous flux maintenance factor.

Example 5 Using the glass of the product 1 of the present invention and the conventional product 1 shown in FIG. 3, the outer diameter of the tube was 32.5 mm and the length was 5 mm.
An 80 mm linear arc tube was made, and a fluorescent lamp with a base attached to both extremes was made. And it lights up at 20W,
The tube wall load was 0.04 W / cm ² . A life lighting test was performed on these two types of glass fluorescent lamps, and 2500
Comparison of the luminous flux maintenance rates at 2,500 hours and 7000 hours shows an average improvement of 1.5% at 2500 hours.
In time, only about 3% improvement effect was recognized.
When this fluorescent lamp was lit and measured in a sealed lighting device, the improvement of the luminous flux maintenance rate was only about 3% as compared with the conventional product 1 in about 2500 hours. The maximum temperature of the lamp is around the electrode.
Met.

However, when the glass of the product 1 of the present invention and the conventional product 1 is processed into a linear arc tube having a tube inner diameter of 14.5 mm and a length of 360 mm, and is lit at a high frequency of about 20 W,
The luminous flux maintenance rate at 2500 hours was about 5% higher for the glass of the present invention 1. In addition, in the case of lighting in a closed appliance whose front surface was covered with light diffusion plastic, the product 1 of the present invention was approximately 1
0% The luminous flux maintenance ratio was higher than that of Conventional Example 1. The temperature of the tube wall in this case exceeded 100 ° C. The tube wall load is 0.
It was 13 W / cm ² . From this, it has been confirmed that, even in a fluorescent lamp using a straight tube, when the tube wall load is high, the effect that the present invention improves the luminous flux maintenance factor by lighting at a high temperature.

[0069]

As described above, the present invention reduces the amount of sodium ions deposited on the inner wall of an arc tube in a fluorescent lamp having a high tube wall load, such as a compact fluorescent lamp and a bulb-type fluorescent lamp. Thereby, it is possible to prevent a decrease in the luminous flux maintenance rate and eliminate blackening of the arc tube and occurrence of black spots. Further, for a compact fluorescent lamp or a bulb-type fluorescent lamp having a tube wall load of 0.13 W / cm ² or more, a decrease in the luminous flux maintenance factor can be suppressed without impairing the workability of the conventional arc tube. . Further, by providing the protective film on the inner wall of the arc tube, precipitation of sodium on the inner wall of the arc tube can be effectively suppressed, and the luminous flux life of the arc tube can be further improved in combination with the above-described glass tube. In addition to the fluorescent lamp having a high tube wall load, if the temperature of at least a part of the luminous tube being lit exceeds 100 ° C., the fluorescent tube, such as a bulb-type fluorescent lamp, may be used. The life of the compact fluorescent lamp in which the lamp and the arc tube are bent can be remarkably improved. Further, it is possible to provide a fluorescent lamp which can reduce the burden on the environment without using any lead, and which can be reduced in cost and weight.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a tube wall load of a fluorescent lamp and a luminous flux maintenance factor after lighting for 2500 hours.

FIG. 2 is a view showing an FPL-type fluorescent lamp according to an embodiment of the present invention;

FIG. 3 shows a comparison between various glass compositions and physical properties.

FIG. 4 is a diagram showing a change over time of a luminous flux maintenance factor of a compact fluorescent lamp.

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Claims (5)

[Claims] 1. A glass tube having a phosphor layer adhered to an inner surface thereof.
Mercury and a rare gas are sealed, the tube wall load is 0.13 W / cm ² or more, and the glass tube contains SiO _{2 in} a weight ratio of 57% to 78%,
More than 0% and 6% or less, SrO 2% or more and 10% or less,
CaO 6% or less, MgO 6% or less, Na ₂ O 4%
Not less than 11%, K ₂ O is not less than 2% and not more than 11%, Li ₂ O
4% or less, B ₂ O ₃ less than 3% 0.5%, P ₂ O less than ₅ 3%, Al ₂ O ₃ 1% or more and 6% or less, the Sb ₂ O ₃ 0
%, 1.5% or less, Fe ₂ O ₃ 0.5% or less, SO
_3. A fluorescent lamp containing 0.5% or less of ₃ . 2. The fluorescent lamp according to claim 1, wherein the arc tube is housed in a glass or resin glove. 3. The fluorescent lamp according to claim 1, wherein a protective film is formed between an inner surface of the glass tube and the phosphor layer. 4. The fluorescent lamp according to claim 3, wherein the protective film is a metal oxide and contains at least one of aluminum, silicon, yttrium, cerium, and titanium as an element. 5. The fluorescent lamp according to claim 1, wherein the inner diameter of the glass tube is 15.0 mm or less.